Announcement

Collapse
No announcement yet.

BenQ TH681 Originally overheating now wont fire the lamp - Colour wheel not starting

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    BenQ TH681 Originally overheating now wont fire the lamp - Colour wheel not starting

    Hi All.

    Does anyone have any reference materials or something I can use to try troubleshooting a BenQ TH681? Google unfortunately has turned up zip. I did find a service manual for a W series BenQ but that is pretty much useless, it's more a glorified user manual. A list of voltages would be great as I suspect my mainboard is faulty, the colour wheel voltage is not dipping like it should.

    The one I am troubleshooting now was originally overheating after a lamp replacement. It originally would take 2 minutes or so for it to shut off and blink the temp and lamp lights red. I found the ZIF socket for the sensor was in the unlocked position so once I sorted that, confirmed the pins on the sensor and the socket itself was fine, and confirmed all the fans/airflow was ok I thought ah easy the ZIF socket was the issue. Nope! When I turned it on it ran fine for about an hour or so than same symptoms. Tried a few more times moving it to a different location to see if it was a fluke to no avail. But if I removed the clear plastic cover that sits on top of the lamp it would run indefinitely.

    I tore it down again and now it comes on for 30 seconds full fan spin red lamp light gives 3 beeps and shuts off. Checking the power to the light sensor I am getting 5v on the power pin but the colour wheel sensor detect signal is not dipping down like it should. I've been watching fix it frank on youtube and he mentioned the line should dip to 2.5 or 2.7 once the wheel fires but it constantly sits at 4.35V until the projector shuts off. Visual inspection returned nothing, all components visually look fine nothing corroded or burned. Traced both the power input from the PSU and the colour wheel connector and made sure there were no shorted components which there weren't.

    So I'm unsure whether I should be looking into the mainboard more or the ballast more. What are the bare minimum components so I can try to eliminate variables? If I disconnect the colour wheel should the projector stay on? If I disconnect the ballast should the projector stay on? Want to get back to bare basics so I can remove variables but I'm unsure what is required and what isn't.

    Thanks for the assistance.

    #2
    Re: BenQ TH681 Originally overheating now wont fire the lamp - Colour wheel not start

    have u watched this? https://www.youtube.com/watch?v=BG3ELt67vxM
    i think it had similiar issue

    Comment

    Working...
    X